From 4e504535c16dfa66290281e704384abfaca08673 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Tue, 25 Oct 2016 04:54:31 +0200 Subject: block/curl: Do not wait for data beyond EOF libcurl will only give us as much data as there is, not more. The block layer will deny requests beyond the end of file for us; but since this block driver is still using a sector-based interface, we can still get in trouble if the file size is not a multiple of 512. While we have already made sure not to attempt transfers beyond the end of the file, we are currently still trying to receive data from there if the original request exceeds the file size. This patch fixes this issue and invokes qemu_iovec_memset() on the iovec's tail. Cc: qemu-stable@nongnu.org Signed-off-by: Max Reitz Message-id: 20161025025431.24714-5-mreitz@redhat.com Signed-off-by: Jeff Cody --- block/curl.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) (limited to 'block/curl.c') diff --git a/block/curl.c b/block/curl.c index 273f329d26..0404c1b5fa 100644 --- a/block/curl.c +++ b/block/curl.c @@ -252,8 +252,17 @@ static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque) continue; if ((s->buf_off >= acb->end)) { + size_t request_length = acb->nb_sectors * BDRV_SECTOR_SIZE; + qemu_iovec_from_buf(acb->qiov, 0, s->orig_buf + acb->start, acb->end - acb->start); + + if (acb->end - acb->start < request_length) { + size_t offset = acb->end - acb->start; + qemu_iovec_memset(acb->qiov, offset, 0, + request_length - offset); + } + acb->common.cb(acb->common.opaque, 0); qemu_aio_unref(acb); s->acb[i] = NULL; @@ -270,6 +279,8 @@ static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len, { int i; size_t end = start + len; + size_t clamped_end = MIN(end, s->len); + size_t clamped_len = clamped_end - start; for (i=0; istates[i]; @@ -284,12 +295,15 @@ static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len, // Does the existing buffer cover our section? if ((start >= state->buf_start) && (start <= buf_end) && - (end >= state->buf_start) && - (end <= buf_end)) + (clamped_end >= state->buf_start) && + (clamped_end <= buf_end)) { char *buf = state->orig_buf + (start - state->buf_start); - qemu_iovec_from_buf(acb->qiov, 0, buf, len); + qemu_iovec_from_buf(acb->qiov, 0, buf, clamped_len); + if (clamped_len < len) { + qemu_iovec_memset(acb->qiov, clamped_len, 0, len - clamped_len); + } acb->common.cb(acb->common.opaque, 0); return FIND_RET_OK; @@ -299,13 +313,13 @@ static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len, if (state->in_use && (start >= state->buf_start) && (start <= buf_fend) && - (end >= state->buf_start) && - (end <= buf_fend)) + (clamped_end >= state->buf_start) && + (clamped_end <= buf_fend)) { int j; acb->start = start - state->buf_start; - acb->end = acb->start + len; + acb->end = acb->start + clamped_len; for (j=0; jacb[j]) { @@ -798,13 +812,13 @@ static void curl_readv_bh_cb(void *p) } acb->start = 0; - acb->end = (acb->nb_sectors * BDRV_SECTOR_SIZE); + acb->end = MIN(acb->nb_sectors * BDRV_SECTOR_SIZE, s->len - start); state->buf_off = 0; g_free(state->orig_buf); state->buf_start = start; - state->buf_len = acb->end + s->readahead_size; - end = MIN(start + state->buf_len, s->len) - 1; + state->buf_len = MIN(acb->end + s->readahead_size, s->len - start); + end = start + state->buf_len - 1; state->orig_buf = g_try_malloc(state->buf_len); if (state->buf_len && state->orig_buf == NULL) { curl_clean_state(state); -- cgit v1.2.3